It's sure to attract as much criticism as it does praise, because Metro is so very different from what went before, but Metro is certainly new to Windows 8. It's also designed to work best with touch-enabled devices, so if you are running a Windows 7 PC without a touchscreen, you may decide that the change is not worth it. There's a lot of dispute about the potential value of touchscreen PCs and laptops, and it is indisputably true that touch is not ideal for typing on an upright screen, for instance. But if you do have a touch-enabled device, you may find that you interact with a Windows 8 PC using your digits a lot more than you expected to.
With our Windows 8 Slate and Bluetooth keyboard setup we find that we've been using the keyboard to type out emails, for instance, but touching the screen to hit send. Windows 7 has touch capabilities, of course, but it's nothing like a true touchscreen OS: with the Metro interface. Windows 8 with Metro is. See also: Windows 8 Tablet review. For more on the changes in Windows 8 and how to use them visit Windows 8 Advisor. For detailed advice on installing Windows 8 Release Preview, read our article: How to install Windows 8.